JPH07235838A - Synthesizer for radio equipment - Google Patents
Synthesizer for radio equipmentInfo
- Publication number
- JPH07235838A JPH07235838A JP4235943A JP23594392A JPH07235838A JP H07235838 A JPH07235838 A JP H07235838A JP 4235943 A JP4235943 A JP 4235943A JP 23594392 A JP23594392 A JP 23594392A JP H07235838 A JPH07235838 A JP H07235838A
- Authority
- JP
- Japan
- Prior art keywords
- signal
- synthesizer
- local oscillator
- frequency
- section
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03C—MODULATION
- H03C3/00—Angle modulation
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/38—Transceivers, i.e. devices in which transmitter and receiver form a structural unit and in which at least one part is used for functions of transmitting and receiving
- H04B1/40—Circuits
- H04B1/403—Circuits using the same oscillator for generating both the transmitter frequency and the receiver local oscillator frequency
- H04B1/405—Circuits using the same oscillator for generating both the transmitter frequency and the receiver local oscillator frequency with multiple discrete channels
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- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Transceivers (AREA)
- Transmitters (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、無線装置、特に無線電
話における無線周波数（ＲＦ）セクション、すなわちＲ
Ｆ送信器セクションおよびＲＦ受信器セクション用の汎
用シンセサイザに関するものである。FIELD OF THE INVENTION This invention relates to radio frequency (RF) sections, or R's, in wireless devices, particularly wireless telephones.
It relates to a general-purpose synthesizer for the F transmitter section and the RF receiver section.
【０００２】[0002]
【従来の技術】一般に使用されている無線周波数セクシ
ョンは、とりわけ使用する変調方式と周波数に関連して
様々である。使用される変調方式の例として、周波数変
調（ＦＭ），直角位相シフトキーイング（ＱＰＳＫ）お
よびガウス最小シフトキーイング（ＧＭＳＫ）が挙げら
れる。The commonly used radio frequency sections vary, inter alia, with regard to the modulation scheme and frequency used. Examples of modulation schemes used include frequency modulation (FM), quadrature phase shift keying (QPSK) and Gaussian minimum shift keying (GMSK).
【０００３】ＦＭ変調方式の場合、変調送信周波数を発
生し得たり、あるいは変調中間周波数を発生し得る位相
同期ループ（ＰＬＬ）シンセサイザを使用することによ
って変調が達成される。In the case of the FM modulation scheme, modulation is achieved by using a phase locked loop (PLL) synthesizer which can generate a modulated transmission frequency or a modulation intermediate frequency.
【０００４】デジタル変調システムの場合、変調周波数
は、例えばアナログ・同相／直角（Ｉ／Ｑ）変調器を使
用することによって発生される。In digital modulation systems, the modulation frequency is generated by using, for example, an analog in-phase / quadrature (I / Q) modulator.
【０００５】[0005]
【発明が解決しようとする課題】このＰＬＬシンセサイ
ザでＦＭ変調周波数を生成するとき、相対する２つの事
柄が生じる。すなわち、一方は、送信器が十分に速い立
ち上がりをもつように位相同期ループのカットオフ周波
数が十分高いことを必要とすることであり、他方は、変
調される信号が上記ループの特性によって歪みを帯びな
いように同カットオフ周波数が十分に低くなければなら
ないことである。また、ＰＬＬシンセサイザの特性は温
度によって左右され、これは、例えば異なる温度で使用
される電圧制御発振器（ＶＣＯ）が中心周波数および周
波数／制御電圧に依存するからである。ＦＭ変調の特性
は、シンセサイザの周波数帯域の動作点、すなわち信号
が送信される送信チャネルに依存する。When generating an FM modulation frequency with this PLL synthesizer, two opposing things occur. That is, one is that the cut-off frequency of the phase-locked loop must be high enough so that the transmitter has a fast enough rise, and the other is that the modulated signal is distorted by the characteristics of the loop. The cut-off frequency must be low enough so that it will not be tinged with. Also, the characteristics of the PLL synthesizer are temperature dependent, for example because a voltage controlled oscillator (VCO) used at different temperatures depends on the center frequency and the frequency / control voltage. The characteristics of FM modulation depend on the operating point of the frequency band of the synthesizer, that is, the transmission channel on which the signal is transmitted.
【０００６】デジタル変調システムにおいて、上記変調
器の解決に必要とされる位相調整（フェージング）を実
現して異なる温度でも特性が最適にあるようにする場
合、アナログＩ／Ｑ変調器の使用は設計者に高度な要求
を与える。In digital modulation systems, the use of analog I / Q modulators is designed to achieve the phase adjustment (fading) required to solve the above modulators so that the characteristics are optimal at different temperatures. People with high demands.
【０００７】[0007]
【課題を解決するための手段】本発明によれば、無線装
置用シンセサイザであって、その無線装置が、無線周波
数信号を受信するためのセクションであって、局部発振
器信号を提供するための局部発振器と、上記無線周波数
信号および局部発振器信号から第１の中間周波数信号を
生成するための混合器とを有する受信器セクションと、
この受信器セクションから送信用の変調無線周波数信号
を生成するためのセクションであって、第２の中間周波
数信号に変調された信号を生成するための手段と、局部
発振器信号を生成するための局部発振器と、上記変調さ
れた中間周波数信号および局部発振器信号から上記変調
された無線周波数信号を生成するための混合器とを有す
る送信器セクションとを具備するシンセサイザにおい
て、上記変調された中間周波数信号を生成するための手
段が直接デジタル合成手段を備え、該直接デジタル合成
手段内で上記変調された中間周波数信号が基準周波数か
ら生成されることを特徴とするシンセサイザが提供され
る。According to the present invention, a synthesizer for a wireless device, the wireless device being a section for receiving a radio frequency signal, the local part for providing a local oscillator signal. A receiver section having an oscillator and a mixer for generating a first intermediate frequency signal from the radio frequency signal and the local oscillator signal;
A section for generating a modulated radio frequency signal for transmission from the receiver section, means for generating a signal modulated to a second intermediate frequency signal, and a local for generating a local oscillator signal. In a synthesizer comprising an oscillator and a transmitter section having a mixer for producing the modulated radio frequency signal from the modulated intermediate frequency signal and a local oscillator signal, the modulated intermediate frequency signal Provided is a synthesizer characterized in that the means for generating comprises a direct digital synthesizing means, in which the modulated intermediate frequency signal is generated from a reference frequency.
【０００８】[0008]
【作用】これにより、本発明は、異なる無線電話システ
ムの無線セクションによって使用され得る統合されたシ
ンセサイザが提供される利点を備える。The present invention thus provides the advantage of providing an integrated synthesizer which can be used by the radio sections of different radio telephone systems.
【０００９】更に、設計と生産が簡素化されるといった
利点も見出される。また、本発明に係るシンセサイザ
は、適用される無線電話システムに応じて、その周波数
が変化し得るといった利点を備える。その上、例えばＦ
ＭとＱＰＳＫの変調等の並列機能を同じ構成で実現でき
るので、例えば、米国のデジタル無線電話システム用に
設計された電話サイズにおいても利点が見出される。In addition, the advantage is found that the design and production are simplified. Further, the synthesizer according to the present invention has an advantage that its frequency can be changed according to the applied wireless telephone system. Moreover, for example, F
Since parallel functions such as M and QPSK modulation can be implemented with the same configuration, advantages will also be found in telephone sizes designed for digital radio telephone systems in the United States, for example.
【００１０】本発明に係るシンセサイザは、無線電話に
おいて直接デジタル合成（ＤＤＳ）の使用を可能にし、
しかもこの直接デジタル合成によって得られる他の利点
を特に犠牲にすることがない。The synthesizer according to the invention enables the use of direct digital synthesis (DDS) in wireless telephones,
Moreover, the other advantages obtained by this direct digital synthesis are not particularly sacrificed.
【００１１】また、上記局部発振器周波数は、その均一
性と精度故に基準周波数として適しており、故に、変調
および所望の中心周波数は、何らかの制御方法によって
デジタル量として供給される。The local oscillator frequency is also suitable as a reference frequency because of its uniformity and precision, so that the modulation and desired center frequency is supplied as a digital quantity by some control method.
【００１２】本発明に係るシンセサイザは、送信器がス
イッチオンしてチャネルに切換わるまでの時間の短縮を
変調の必要条件に関係なく可能にする。これによりバッ
テリ電力が節約され、これは携帯用無線電話にあっては
欠くことのできない要素である。The synthesizer according to the invention makes it possible to reduce the time it takes for the transmitter to switch on and switch to the channel, regardless of the modulation requirements. This saves battery power, which is an integral part of portable wireless phones.
【００１３】本発明の実施例は、本発明のシンセサイザ
の概略的なブロック図である図１を参考にして以下に述
べられるが、これは１つの例に過ぎない。An embodiment of the invention is described below with reference to FIG. 1, which is a schematic block diagram of a synthesizer of the invention, but this is only one example.
【００１４】[0014]
【実施例】従来の技術で熟知されているように、無線装
置の無線セクションは、受信器セクションと送信器セク
ションとを備えている。DETAILED DESCRIPTION OF THE INVENTION As is well known in the art, the radio section of a wireless device comprises a receiver section and a transmitter section.
【００１５】無線装置の受信器セクションは、受信され
た信号が混合器内で局部発振器信号と組み合わされて、
低い固定周波数の中間周波数（ＩＦ）信号に変換され
る。この中間周波数信号は、更に、増幅された後、受信
信号内に含まれる元の情報を再生するために検波され
る。これもまた当業者おいて熟知されているので、ここ
ではこれ以上詳細に述べないこととする。The receiver section of the wireless device comprises a received signal combined with a local oscillator signal in a mixer,
It is converted to a low fixed frequency intermediate frequency (IF) signal. This intermediate frequency signal is further amplified and then detected to recover the original information contained in the received signal. This is also well known to those skilled in the art and will not be described in further detail here.
【００１６】図１において、受信器セクションにある混
合器８用の局部発振器は、通常、位相同期ループ（以
後、ＰＬＬ）を備えるシンセサイザ１によって実現され
る。このＰＬＬの出力信号Ｒｘは、シンセサイザ１と結
合された基準周波数発振器２により供給される基準周波
数に公知の方法を用いて固定された周波数を有する。基
準周波数は、例えば温度補償付き水晶発振器（ＴＣＸ
Ｏ）によって発生される。更に、上記ＴＣＸＯは電圧制
御されても良く、すなわちＶＣＴＣＸＯ（電圧制御温度
補償付き水晶発振器）でも良い。温度補償に加えて、Ｐ
ＬＬの出力周波数は自動的な周波数制御によって、例え
ば、受信された信号の入力周波数に固定され得る。In FIG. 1, the local oscillator for the mixer 8 in the receiver section is usually realized by a synthesizer 1 with a phase locked loop (hereinafter PLL). The output signal Rx of this PLL has a frequency fixed using known methods to a reference frequency provided by a reference frequency oscillator 2 coupled to the synthesizer 1. The reference frequency is, for example, a crystal oscillator with temperature compensation (TCX).
O). Further, the TCXO may be voltage-controlled, that is, VCTCXO (crystal oscillator with voltage-controlled temperature compensation). In addition to temperature compensation, P
The output frequency of the LL can be fixed, for example, to the input frequency of the received signal by automatic frequency control.
【００１７】上述のように受信セクションで使用される
と同様に、出力信号ＲｘはＤＤＳシステム３にも供給さ
れる。The output signal Rx is also supplied to the DDS system 3, similar to that used in the receiving section as described above.
【００１８】直接デジタル合成（ＤＤＳ）システムは、
ディジタル／アナログ変換器（ＤＡＣ）を用いて基準周
波数からデジタル的に発生される正弦波を提供するシス
テムである。典型的なＤＤＳシステムは、ＤＤＳマイク
ロ回路，ＤＡＣ、クロック信号発生器およびデジタル・
インタ−フェイスを備えている。ＤＤＳによって提供さ
れる周波数分解能は高精密度であり、例えば３０ＭＨｚ
の周波数で約０．００７Ｈｚである。そして、この信号
の位相分解能も非常に高精密度である（約０．００００
０００８度）。ＤＤＳシステムは小電力消費で小型であ
る。従って、ＤＤＳシンセサイザは、周波数シフトまた
は位相シフトの後、瞬時の立ち上がりを必要とする用途
に有効である。係る用途には、周波数ホッピング，位相
シフトキ−イング（ＰＳＫ）モ−ド，可変型トランシ−
バ−，何らかの広帯域システム及び信号発生器を実現し
得るモ−ドが含まれる。遠隔通信システムにおいてＤＤ
Ｓシンセサイザは、局部発振器及び変調器として両方に
使用できる。更に、搬送波に固定している状態、つまり
ビット同期状態において、ＶＣＯにとって代わることも
できる。Direct Digital Synthesis (DDS) systems are
A system for providing a digitally generated sine wave from a reference frequency using a digital-to-analog converter (DAC). Typical DDS systems include DDS microcircuits, DACs, clock signal generators and digital
It has an interface. The frequency resolution provided by the DDS is of high precision, eg 30MHz
The frequency is about 0.007 Hz. And the phase resolution of this signal is also very high precision (about 0.0000).
0008 degrees). DDS systems are small in power consumption and small in size. Therefore, the DDS synthesizer is effective for applications that require an instantaneous rise after frequency shift or phase shift. Such applications include frequency hopping, phase shift keying (PSK) mode, and variable transfer.
Included is a mode capable of implementing a bar, any wideband system and signal generator. DD in telecommunication systems
The S synthesizer can be used both as a local oscillator and a modulator. Furthermore, it can also replace the VCO in the state where it is fixed to the carrier wave, that is, in the bit synchronization state.
【００１９】無線装置の送信器セクションの出力信号Ｔ
ｘは、混合器４内で、シフト発振器信号Ｓｏと、シンセ
サイザ−１からの出力信号Ｒｘとを混合することによっ
て生成される。シフト発振器信号ＳｏはＤＤＳシステム
３内で生成され、シンセサイザ−１からの出力信号Ｒｘ
をもつ変調を含んでいる。ＤＤＳシステム３の出力と混
合器４との間に乗算器５が設けられて、混合に適するよ
うにＤＤＳシステム３からの信号を増大させても良い。
加えて、ＤＤＳシステム３と混合器４の間、及び混合器
４の後段に結合された各フィルタ６及び７を用いて、結
合処理による余計な結果およびスプリアス送信を取り除
くことができる。The output signal T of the transmitter section of the wireless device
x is generated in the mixer 4 by mixing the shift oscillator signal So with the output signal Rx from synthesizer-1. The shift oscillator signal So is generated in the DDS system 3, and the output signal Rx from the synthesizer-1 is generated.
It contains a modulation with. A multiplier 5 may be provided between the output of the DDS system 3 and the mixer 4 to increase the signal from the DDS system 3 for mixing.
In addition, the filters 6 and 7 coupled between the DDS system 3 and the mixer 4 and after the mixer 4 can be used to remove extra results and spurious transmissions due to the coupling process.
【００２０】局部発振器、すなわちシンセサイザ１は、
ＤＤＳシステム３に基準周波数を提供するために使用さ
れ、これによりＤＤＳシステムの中心周波数が制御され
ることを可能にする。The local oscillator, or synthesizer 1, is
Used to provide a reference frequency to the DDS system 3, which allows the center frequency of the DDS system to be controlled.
【００２１】ＤＤＳシステムの基準周波数は、ＤＤＳシ
ステムの出力信号の数倍（少なくとも２倍）でなければ
ならない。その時、高い出力周波数と温度ドリフトのた
めに、無線電話で基準周波数を発生させることが課題で
ある。一方で別の発振器によって基準周波数を発生させ
ることも可能であるが、これは余計な費用がかかりスペ
−スも必要となる。The reference frequency of the DDS system must be several times (at least twice) the output signal of the DDS system. The challenge then is to generate a reference frequency in the radiotelephone due to the high output frequency and temperature drift. On the other hand, it is possible to generate the reference frequency by another oscillator, but this is extra cost and requires a space.
【００２２】ＤＤＳシステム４を用いて、例えばＦＭ，
ＱＰＳＫ及びＧＭＳＫ変調等、多くの異なる変調を実現
することができる。このような変調と望ましい中心周波
数はディジタル形式でＤＤＳに供される。これらは個々
または共通の物理的インタ−フェイスを備えることがで
きる。Using the DDS system 4, for example, FM,
Many different modulations can be implemented, such as QPSK and GMSK modulation. Such modulation and the desired center frequency are provided to the DDS in digital form. These can have individual or common physical interfaces.
【００２３】局部発振器周波数は、従来、ＤＤＳシステ
ム３からのシフト発振器周波数、すなわち出力Ｓｏの数
倍（２倍から１０倍）の周波数である。その上、もしＤ
ＤＳシステム３と混合器４の間に乗算器が使用された場
合、ＤＤＳの出力Ｓｏと局部発振器周波数との差は益々
大きくなる。局部発振器周波数はチャネルによって変化
するけれども、正確な送信器周波数は、ＤＤＳ周波数を
チャネルに対応して調節することによって維持される。The local oscillator frequency is conventionally a shift oscillator frequency from the DDS system 3, that is, a frequency several times (2 to 10 times) the output So. Besides, if D
If a multiplier is used between the DS system 3 and the mixer 4, the difference between the output So of the DDS and the local oscillator frequency becomes even larger. Although the local oscillator frequency varies from channel to channel, the correct transmitter frequency is maintained by adjusting the DDS frequency for the channel.
【００２４】ここで、もし局部発振器信号を発生するシ
ンセサイザ単独で送受信チャネルをカバ−しようとする
と、位相誤差や位相ロック時間に関しての問題が生じ
る。周波数帯域制御の一部はＤＤＳによって処理され得
る。Here, if the synthesizer for generating the local oscillator signal alone attempts to cover the transmission / reception channel, problems with phase error and phase lock time occur. Part of the frequency band control can be handled by the DDS.
【００２５】[0025]
【発明の効果】この構成は、アナログシステムとディジ
タルシステムの両方で使用され得るので、無線装置がア
ナログ及びディジタルモ−ドの両方で使用される必要の
ある、例えば米国で計画されている時分割多重アクセス
（ＴＤＭＡ）システムにおいて特に最適とされる。Since this arrangement can be used in both analog and digital systems, it is necessary for radio equipment to be used in both analog and digital modes, such as the time-sharing scheme planned in the United States. It is especially optimized in multiple access (TDMA) systems.
【００２６】上述の記述から、当業者にとっては本発明
の範囲内で各種の変形例が可能であることは明らかであ
ろう。From the above description, it will be apparent to those skilled in the art that various modifications are possible within the scope of the present invention.
【図１】本発明に係るシンセサイザの概略ブロック図で
ある。FIG. 1 is a schematic block diagram of a synthesizer according to the present invention.
１…シンセサイザ ２…基準周波数発振器 ３…ＤＤＳシステム ４…混合器 ５…乗算器 ６，７…フィルタ ８…混合器 DESCRIPTION OF SYMBOLS 1 ... Synthesizer 2 ... Reference frequency oscillator 3 ... DDS system 4 ... Mixer 5 ... Multiplier 6,7 ... Filter 8 ... Mixer
Claims (5)
無線装置が、 無線周波数を受信するためのセクションであって、局部
発振器信号を提供するための局部発振器と、前記無線周
波数信号および局部発振器信号から第１の中間周波数信
号を発生するための混合器とを有する受信器セクション
と、送信用の変調された無線周波数信号を発生するため
のセクションであって、第２の中間周波数信号に変調さ
れた周波数信号を発生するための手段と、局部発振器信
号を発生するための局部発振器と、該変調された中間周
波数信号および該局部発振器信号から前記変調された無
線周波数信号を発生するための混合器とを有する送信器
セクションとを具備するシンセサイザにおいて、 前記変調された中間周波数信号を発生するための手段が
直接ディジタル合成システムを具備し、該直接ディジタ
ル合成システム内で該変調された中間周波数信号が基準
周波数から発生されることを特徴とする無線装置用のシ
ンセサイザ。1. A synthesizer for a wireless device, wherein the wireless device is a section for receiving a radio frequency, a local oscillator for providing a local oscillator signal, the radio frequency signal and the local oscillator. A receiver section having a mixer for generating a first intermediate frequency signal from the signal and a section for generating a modulated radio frequency signal for transmission, the section modulating to a second intermediate frequency signal Means for generating a modulated frequency signal, a local oscillator for generating a local oscillator signal, and a mixture for generating the modulated radio frequency signal from the modulated intermediate frequency signal and the local oscillator signal A transmitter section having a transmitter, the means for generating the modulated intermediate frequency signal being a direct digital signal. Comprising a Le synthesis system, synthesizer for wireless device, wherein an intermediate frequency signal which is said modulated in the direct digital synthesis system is generated from the reference frequency.
信用無線周波数信号に周波数制御を行うように動作可能
であることを特徴とする請求項１に記載のシンセサイ
ザ。2. The synthesizer of claim 1, wherein the direct digital synthesis system is operable to perform frequency control on a radio frequency signal for transmission.
は、前記受信機セクションの局部発振器によって発生さ
れることを特徴とする請求項１または２のいずれか１項
に記載のシンセサイザ。3. Synthesizer according to claim 1 or 2, characterized in that the oscillator signal for the transmitter section is generated by a local oscillator of the receiver section.
Ｓ）と送信機用混合器との間に乗算器（５）が設けら
れ、混合に適するようにＤＤＳ周波数を増大させること
を特徴とする請求項１から３のいずれか１項に記載のシ
ンセサイザ。4. The direct digital synthesis system (DD)
4. A synthesizer according to any one of claims 1 to 3, characterized in that a multiplier (5) is provided between S) and the transmitter mixer to increase the DDS frequency to suit the mixing. .
数は、ＰＬＬシンセサイザ（１）の支援によって発生さ
れることを特徴とする請求項２に記載のシンセサイザ。5. Synthesizer according to claim 2, characterized in that the local oscillator frequency of the receiver section is generated with the aid of a PLL synthesizer (1).
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FI914181A FI89845C (en) | 1991-09-04 | 1991-09-04 | Connection for generating broadcast signal in a radio telephone |
| FI914181 | 1991-09-04 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH07235838A true JPH07235838A (en) | 1995-09-05 |
| JP3200184B2 JP3200184B2 (en) | 2001-08-20 |
Family
ID=8533075
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP23594392A Expired - Fee Related JP3200184B2 (en) | 1991-09-04 | 1992-09-03 | Synthesizer for wireless devices |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US5301367A (en) |
| EP (1) | EP0535800B1 (en) |
| JP (1) | JP3200184B2 (en) |
| DE (1) | DE69223373T2 (en) |
| FI (1) | FI89845C (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003110434A (en) * | 2001-09-28 | 2003-04-11 | Alps Electric Co Ltd | Transmission level setting method |
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| FI89845C (en) * | 1991-09-04 | 1993-11-25 | Nokia Mobile Phones Ltd | Connection for generating broadcast signal in a radio telephone |
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| GB2320632B (en) * | 1996-12-23 | 2001-09-05 | Nokia Mobile Phones Ltd | Method and apparatus for transmitting and receiving signals |
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-
1991
- 1991-09-04 FI FI914181A patent/FI89845C/en active
-
1992
- 1992-08-25 US US07/934,927 patent/US5301367A/en not_active Expired - Lifetime
- 1992-08-26 DE DE69223373T patent/DE69223373T2/en not_active Expired - Lifetime
- 1992-08-26 EP EP92307770A patent/EP0535800B1/en not_active Expired - Lifetime
- 1992-09-03 JP JP23594392A patent/JP3200184B2/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003110434A (en) * | 2001-09-28 | 2003-04-11 | Alps Electric Co Ltd | Transmission level setting method |
Also Published As
| Publication number | Publication date |
|---|---|
| FI914181A (en) | 1993-03-05 |
| DE69223373D1 (en) | 1998-01-15 |
| US5301367A (en) | 1994-04-05 |
| FI914181A0 (en) | 1991-09-04 |
| EP0535800A2 (en) | 1993-04-07 |
| FI89845B (en) | 1993-08-13 |
| JP3200184B2 (en) | 2001-08-20 |
| EP0535800A3 (en) | 1993-08-11 |
| FI89845C (en) | 1993-11-25 |
| DE69223373T2 (en) | 1998-04-09 |
| EP0535800B1 (en) | 1997-12-03 |
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